The End of the Inline-Four – The V2 Era Begins

The 600cc four-cylinders are dying out. Euro 5+ and declining unit numbers are making twins the new benchmark for the middleweight class: more torque, less rev hysteria, more character.

Anyone who still saw CBR 600 RR, GSX-R 600 or Daytona 675 in the showroom in 2017 is now looking at the Panigale V2 FB63, Aprilia RS 660, KTM 990 Duke R and soon the BMW F 450 GS. The inline-four below 1000 cc is dying out – and there are solid reasons for that.

Why the inline-four is dying

Three factors are killing the classic 600 class:

• Euro 5+ from 2025: High-revving R4 engines are now barely homologatable in terms of emissions, noise and fuel evaporation.
• Development costs: An emissions-compliant 600cc R4 exceeds €1.5 million – with falling demand, it no longer pays off.
• Market shift: Buyers are moving to naked bikes, adventure tourers and practical twins.

Why the V2 wins

The Ducati twin in the Panigale V2 FB63 already delivers more than 70% of its maximum torque from 3,000 rpm – the old 600cc R4s only reached their peak power at 13,000+ rpm. On the road, that is simply unusable.

Added to that are:

• 30,000 km valve clearance interval (instead of complex R4 maintenance)
• Lower complexity, less weight
• Natural balance thanks to the 90° V configuration
• Euro 5+ significantly easier to meet

The new middleweight class in figures

The Panigale V2 FB63 is the current tribute to Álvaro Bautista, the two-time Superbike World Champion who played a major role in shaping the rise of Ducati twins.

Motorsport follows suit

The WorldSSP has allowed twins of up to 1000 cc since 2022 – and Ducati dominates the class. Even MotoGP will reduce to 850 cc from 2027, and Yamaha is switching there from the inline-four to the V4 engine. The R4 as a sacred concept belongs to the past.

Conclusion

My impression: the V2 is not the compromise it is often sold as – it is the more honest answer. Peak hp on the spec sheet count for less than torque in the everyday rev range, and that is exactly what modern twins deliver. Anyone still waiting for a new 600cc R4 is waiting in vain. The inline-four remains – but as a 1000cc superbike concept, no longer in the middleweight class.